1. Field of the Invention
The present invention relates to a recording tape cartridge accommodating, within a case, a single reel on which is wound a recording tape, such as a magnetic tape or the like, which is used as a recording/playback medium mainly in computers or the like.
2. Description of the Related Art
Conventionally, magnetic tape cartridges have been known in which a magnetic tape, which is used as a data recording/playback medium of a computer or the like, is wound on a single reel, and the reel is accommodated in a case. A leader member, such as a leader pin, a leader tape, or a leader block, is provided at the distal end of the magnetic tape. A pull-out mechanism provided at a drive device pulls the leader member out from an opening of the magnetic tape cartridge, and winds the magnetic tape fixed thereto onto a take-up reel of the drive device.
An open hole is formed in the bottom surface of the magnetic tape cartridge. A reel gear is formed in an annular form in the center of the bottom surface of the reel which emerges from the open hole. Due to a driving gear, which is provided at a rotating shaft of the drive device, meshing with this reel gear, the reel is driven to rotate. By driving the reel of the magnetic tape cartridge and the take-up reel of the drive device synchronously, data can be recorded onto the magnetic tape, and data recorded on the magnetic tape can be played back.
Little accommodating space is required at the time of storing the magnetic tape cartridge having such a structure, and a large amount of information can be recorded in the magnetic tape cartridge. The position of the opening and the type of the door which opens and closes the opening differ for each type of leader member. Namely, for example, when a leader pin 70 is used, as shown in FIG. 8, an opening 68 is formed in a side wall 64 of a case 62, which side wall 64 is parallel to the direction of loading the magnetic tape cartridge in a drive device (the direction of arrow P). The opening 68 is opened and closed by a door 66 which slides in the same direction as the loading direction.
A coil spring 67 is fit on a shaft 65 which projects from the rear end portion of this type of door 66. The rear end portion of the coil spring 67 is anchored on an anchor portion 69 provided at the case 62. The door 66 is thereby assembled within the case 62. In this way, the door 66 is usually urged in the direction of closing the opening 68. As the magnetic tape cartridge is loaded into a drive device, the door 66 slides in the direction opposite to the direction of arrow P, and opens the opening 68.
However, at the time of assembling this type of door 66 into the case 62, the work for anchoring the rear end portion of the coil spring 67 on the anchor portion 69 must be carried out. It is easy for this assembly operation to become complex, and the assembly performance (assemblability) of the coil spring 67 is not always good.